Method of applying temporary protective coatings



May 11, 1948. B. M. PINELES METHOD OF APPLYING TEMPORARY PROTECTIVECOATINGS 2 Sheets-Sheet 1 Filed April 27, 1944 y 1948 B. AM. PINELES' 723443 22"? METHOD OF APPLYING TEMPORARY PROTECTIVE COATINGS Filed April27, 1944 2 Sheets-Sheet 2 lnmmiar Bei'na I'd/1 fine/ea Patented May '11,1948 PROTECTIVE COATINGS Bernard M. Bineles,

United Shoe ton, N. J., a corporation Corporation, oi New JerseyHamilton, Mass assignor to Flc lnlr Application April 27, 1944, SerialNo. 538,015

3 Claims.

1 'This invention relates to the method of applying by means of a spraya temporary protective coating of a film-forming colloid, which may bereadily peeled or article having gaps or openings in its surface.

Many articles, to which films or coatings are to be applied, have gapsor openings in their surfaces. For example, the barrel of a machine gunis commonly surrounded by a hollow supporting jacketv the wall of whichhas holes in it, and there are larger openings in the walls whichenclose the firing mechanism. Examples of larger articles havingopenings which lead into their interiors are automobiles and airplanes.When such articles are to be coated it is desirable first to cover orbridge over all openings, except perhaps in certain cases very smallones, before applying to the article its temporary protective film orcoating. It is possible, of course. to cover such openings by means ofsome extraneous material such as cloth, paper or adhesive tape, and thento spray on the solution oi film-forming colloid.

According to the present invention the gaps or paratively dry; and thenover these bridging coatings and over uncoated portions of the articlethere is applied, by means of a spray, the particles of which aresmaller, probably globular or nearly so, and wetter than those of thebridging spray, a coating which amalgamates with and adheres firmly tothe'bridging coatings to form a tough, flexible, temporary protectivecoating which adheres lightly to the article and may be readily peeledor stripped off when desired. In practice a spray gun may be coating asmay be desired.

Fig. 3 is a perspective of the same machine gun as is shown in Fig. 1after all the openings have been covered by a bridging coating ofcomparatively dry filaments, and then a second superstripped oil whendesired, to an NT OFFICE G TEMPORARY l posed coating has beenamalgamated with the lightly adherent bridgin v tegral coating coveringthe entire which may stripped of! when desired.

upside 9, ll (both being one post receiving an en .The machine gun I whicoat'ingto' form an inch is. tobe coatedis down upon two crotched postsshown in Fig. 3), the crotch of a the d of thebarrel, and the receivingaportionlof a rear of thegun. The

expose all parts 'of its surface to the action of. a

spray which issues from a the operator in one hand w rotates the machinThe spray gun sion of spray from the m trolled by a trigger two valves2|, 23 w by turning their controls'the fiow air throughtwo 25 which is--fast to shown) being pro upon the spray closed and the the general formto spray material passin is so adjusted that t globular or nearly so athe, regular wet s trols the flowof original position; 68 supply moreair a of 89m as to provide more into the fan-shape shown. is closed, thespray has the the proportion of air to s than when the valve 2| to thespray gun, from an air shown) through a "tube .21, the air compressorand the s shown) manipulation 01 Win of the air. A seco of supply (notshown) under tion'of spray material to..a

Spray.

spray gun I'I held by hile with the other he e gun as may be desired. acommercialtone, the emis-v ain nozzle being con- IS;' The gun isprovided with hich may be opened and closed knurledheads. The valve 23air and to 'fiatten the spray y material. The valve 2! does not controlthe flow of air throu gh the main nozzle. When opened, it permits fiowof extra small auxiliary nozzles 24,25 soout the spray :F When thevalve-2l. shape or a cone, and pray material is less pray guna valve(not ch varies the pressure nd tube 29 leads from a source I pressure ofthe solusmall receptacle 3! gun, a valve (notf vided for varying thepressure material. When the valve 2| is as has been stated, has

of a cone, the proportion of air through the main nozzle he particles ofspray are nd contain acomparatively large amount of solvent, this spraybeing termed as, distinguished from the rticles of which are in thelong, comparatively dry' spray may be produced by n of spray'material toair, ngto a larger extent the valve i wever, the valve 23, whichconspray material, remains Lin-its.

and the valve 2 t is nd to flatten'out the opened to spray into openinsthe fan-shaped spray it shown, a comparatively thin fiat fan-shapedspray bridging certain openings in a pears below.

manner which apto the rim of the opening, and there res at random. anthe large openings, means of this bridging coating, the proportion ofspray material to air is again adjusted to produce thespray referred toabove as the regular wet spray, the particles of which are globular, ornearlyso and contain a greater proportion of solvent to solid when theystrike the e Si F; used to apply a coating and over uncoated portions ofthe machine gun. The superposed coating adheres firmly to andamalgamates with the bridgin coatings to form an'integral coating which,like the bridging coatings, adheres lightlyto the articles. somewhatdrier than the regular spray and is referred to herein asa spray oflong, comparatively dry filaments. lightly adherent coating; thefollowing comparaspray forms a coating which amalwith the bridgingcoating and adheres lightly to the article; and there results a singlecoating which mayreadiiy off.

with regard to the,term-"lightlyjadherent," the filaments adhere in acertain degree to the article and in a greater degree to each other sovthat a brid coating of filaments more or less entangled and superposedat angles upon others beneaththem is formed which remains in place whilethe somewhat wetter, more or less globular particles or the followingspray are deposited $119 tins which amalgamates cl es peins theltlis nobridglnil partly laminated coating readily peeled or stripped of! whendesired. The above is true even though the article to be coated has uponit, as frequently happens when the article is a machine-mm. a thincoating of light lubricating oil. At least it is certain that thebridgin coating above circumstances. As to the following coating inthecase of an article such as a ma hine gun which has a light coating ofoil, it may be that the lightly. adherent quality of the envelopingcoating is due in large measure to the shrinkin which takes place whenthe solvent evaporates.

Thereis, of'course, a limit to the size of an which may be bridged bythe spray of filaments. Just what the limit is, "but an opening, thesmallest dimension of which (is about 8", may readily be bridg d. y v

coating, the amalgamated being capable of being being preferable in ultsa The spray of filaments is be peeled or stripped adheres lightly evenunder the- I in its top, said' opening being that is,

This spray results in a .Presently other filaments adhere large articlesor objects, such, for example, as airplane wheel housings have largeropenings, and consequently in general no difllculty is encountered. Fig.2, which is illustrative of how the bridging is done, shows a generallycylindri: cal ceramic vessel 3| with a circular openin considered forpurposes ofdiscussion to have a diameter of 83'. The spray, as has is athin, fanshaped one. The filaments do not need, in this case, to be 8"long. They may he, say, l"-3" long. As the spray strikes the locality ofthe rim of the receptacle nearest to the spray gun, some or thesetraveling filaments adhere to the rim and extendto some extent over theopening. to the free ends of the first filaments; and this processproceeds with following filaments until the filaments added one toanother extend across the opening. The fan-shaped spray is held at acomparatively small angle to the plane of the opening. which in thefigure is horizontal, and is swim! back and forth in an arc whilemaintaining the angle substantially constant. There thus results abridging coating made up of a network of filaments arranged at random,more or less tangled, and extending at different angles over othersbeneath them.

Assuming that the proportion of compressed air .to spray materialpassing through the spray gun is such that the spray is what has beentermed the regular spray and consists of globular or similarly shapedparticles which, with the nozzle of the spray gun held at a convenientdistance, says or 6 inches, from the article, will produce what has beentermed the wet coating,

one which will dry out to a tough, he:- adherent film, the procedure ofapprotective coating to an article, such, for example, as 'a machinegun, which has openings in its surface, is as follows. The proportion ofcompressed air to spray material is increased, the valve 2! beingpreferably opened somewhat. There is thus produced a thin fanshapedspray the particles of which are comparatively long,. comparatively dryfilaments. The spray gun is preferably held farther from the article,say 15', the bridging coatings.

lble, lightly p yi a tempora In the above specific have been given, thepressure upon the spray material may be 15 lbs. per square inch and thaton the air 30 lbs. per square inch. After the openings have all beenbridged by the use of this spray. the proportion of compressed air tospray material is decreased once more, for example, by closing the valve21 to produce the regular spray of globular or similarly shapedparticles which contain more solvent when they strike the articles thandid the filaments of the bridging spray. The spraying is then continuedwith the spray gun held at, say. 4 or 5 inches from the article, toapply over the bridg ng coatings and over uncoated portions of thearticle what has been termed the regular wet coating, which amalgamateswith the bridging coatings to produce with said bridging coatings asingle coating which may be readily peeled or stripped oil when desired.There has been described above a brid during the application ofcompatible so that one coating will amalgamate with the other.

It is possible to use the regular spray to produce both the bridgingcoating and the superposed regular coating by first holding the sprayregular coating; but this procedure has the disadvantage that, when thespray gun is held at a suflicient distance from the article to producesuitable filaments, only a comparatively small number 01' sprayparticles strike the article at any iven moment so that a considerablepart oi the spray material. is wasted. and bridging the openingsrequires a much longer application or the spray. The other possibility,namely to make use only or the bridging spray sun close to the articleto that holes are liable to be made in the bridging coating. Below areseveral examples of spray material.

Example I Parts by weight Vinylite VYNS Acetone 85 Vinylite VYNS, aproduct oi' Carbide and Carbon Chemicals Example It Parts by weigh: 1

Vinylite VYN 3GH 5 85 Acetone 38H, a product of Carbide and CarbonChemicals Corporation, of New York, is triethylene glycol dl-2-ethylbutyrate and is a plasticizer specially designed for use with Vinyliteresins.

Example III 1 Parts by weight Vinylite XYBG 10 Methanol 90 Example IVParts by weight Vinylite XYSG 8 3GH 4 Methanol 88 Vinylite XYSG. aproduct oi Carbide and Carbon Chemicals Corporation, of New York, is anacetal which results from reacting polyvinyl alcohol with butyraldehyde.

Example V Parts by weight Polymerized methyl methacrylate 10 Ethylenedichloride 90 Example VI Parts by weight Polymerized methyl methacrylate--10 Dibutyl phthalate 5 Ethylene dichloride 5 In the above example thespray material con- 76 filaments or film-forming sists of a resin and asolvent withor without a plasticizer. It should be understood, however.that various other ingredients may be used it desired. For example. thespray material may have the following composition which. since itcontains a corrosion inhibitor, forms part of the subjectmatter ofapplication serial No. 736,514, filed March 22, 1947, which is a Oil1255, a non-corrosive, non-drying oil, is 'a product oi. the StandardOil Company of New Jersey.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. The method 01' applying a temporary protective coating to an articlehaving an opening in oil when desired.

2. The method of applying a temporary protective coating to an articlehaving an opening in a wall thereof, said method comprising providing aspray material in the form of a vinyl resin or a gas under form ofcomparatively long, comparatively dry colloidal material to travel overthe opening in such manner as to build upi-e. bridging coating, and thencousin: 0, generally cone-shaped spray the particles 01 which aresmaller and wetter than the filaments to travel over the bridgingcoating and over ancoated portions 01 the article to form with thebridging coating a tough, flexible temporary protective coating whichadheres iizhtiy and ma be readily stripped of! when desired.

' BERNARD M. PINELEB.

nnrnnnncns crmn The loilowina references are or record in the file 0!this patent:

" um'mn sums PATENTS Number Number I Name Date Moyses Apr. 10, 1934Ericson Mar. 28, 1943 FOREIGN PATENTS Country Date Great Britain Mar.3,1948

